PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 75 



/. 11 Head large, broad, flat, not keeled, 4.25 in total length, equal to depth 

 of body : muzzle obtuse : eye nearly 5 times in head : scales (small, as 

 in var. pleuriticus) 42 below first dorsal ray : dorsal fin equidistant : 

 caudal fin not notched. Kansas River." — (Cope.) stomias.* 



ff. Head comparatively large, and long acuminate, .25 of length, its outline 

 as a whole pointed, but the muzzle itself bluntish, its upper surface 

 not much convex in either direction, very slightly carinated: mouth 

 medium, the maxillary moderate, .12 of length, not reaching much 

 beyond eye : patch of hyoid teeth small, and comparatively weak : 

 body elongate, not greatly compressed, the depth .25 of length : 

 dorsal fin small, its last rays f the height of the first: caudal fin 

 short, quite distinctly forked : scales small, in 160 to 184 transverse 

 rows: colors rather dark, back and sides more or less profusely 

 covered with small rounded spots. Streams of California west of 

 the Sierra Nevadas; Lake Tahoe HENSHAWi.t 



fff. Head comparatively short and thick, .22 to .25 of length, its outline 

 more convex, more or less distinctly carinated above : mouth rather 

 small, but larger than in irideus, the maxillary not reaching far be- 

 yond the eye : patch of hyoid teeth well developed : body modera.tely 

 elongate, compressed; depth .24 of length: dorsal fin rather low, 

 its last rays f the height of the first : caudal fin scarcely forked, 

 rather more so than in spilurus : scales moderate or rather small: 

 colors variable, the back and sides usually profusely, but variably 

 spotted, silvery in sea-run individuals. Rio Grande to Upper Mis- 

 souri and west to the Pacific clarki. 



y. Scales moderate, in 155 to 165 rows ; chiefly west of the Rocky 



Mountains Subspecies clarki. 



yy. Scales small, in 165 to 170 rows ; chiefly east of the Rocky Mount- 

 ains Subspecies aurora. 



The American species of this subgenus Salar are very closely inter- 

 related, and might almost be considered as varieties of a single poly- 

 morphous species. The occurrence of forms apparently intermediate 

 prevents me from considering aurora and pleuriticus as distinct species, 

 although they may usually be readily recognized. 



Of the true subgenus Salmo, there seems to be but one species in 

 America, the Salmo salar, our specimens being, so far as I can see, pre- 

 cisely identical with the European. The land-locked Salmon of Maine, 

 Salmo sebago, Girard, does not differ by any constant character from 

 Salmo salar, and its permanent residence in fresh water is the only 

 character of which I know on which a subspecies sebago could be based. 

 Laud-locked Salmon from Bergen, Sweden, in the United States National 

 Museum, and laud-locked Salmon from Sysladobsis Lake, Maine, are to 

 my eye precisely alike, and both are Salmo salar, Linnaeus. 



* Salmo stomias Cope, 1872. — 1 have not seen this species, but Professor Cope writes 

 me that if I had, I would certainly consider it specifically distinct from S. pleuriticus. 

 Since the above was in type, I have examined a head of a large specimen of Salmo 

 stomias from the Upper Missouri. It agrees fully with Professor Cope's description. As 

 it is a species with well-developed hyoid teeth, it is related to S. clarki, and S. hen- 

 shawi, differing in the peculiar form of the head and the smaller size of the scales. 



t Salmo henshawi Gill & Jordan, Jordan, Man. Vert. ed. 2d, p. 358, 1878.— This fine 

 species is named in honor of Mr. H. W. Henshaw, the well-known ornithologist, who 

 first brought specimens from Lake Tahoe. 



